University of Bristol opens up its quantum processor

The University of Bristol is to provide public access to its quantum computing processor later this month, allowing people to experiment with quantum entanglement and superposition.

The University of Bristol's School of Physics is to become the first establishment in the world to provide public access to a quantum computing system, in an effort to make the concept easier for people to grasp.

Traditional computing, as readers of this site will be very aware, works on a binary principle: the smallest unit of computer logic is the 'bit,' which can be either zero or one. The language may differ depending on what you're doing - false and true, off and on - but the bit remains the same. Some progress has been made in so-called trinary systems, which replace the bit with a three-state trit - jokingly claimed to have as its states yes, no and maybe - and there are historical dernary systems which counted in base-10 like humans, but binary is the predominant paradigm.

Quantum computing is a lot like binary, in that each bit of a quantum processor has a zero state and a one state. Unlike a traditional processor, however, a quantum processor holds each bit in 'superposition' - meaning it is both zero and one simultaneously.

It's a concept that's hard to grasp, and which for many draws parallels with Erwin Schrödinger's famous thought experiment of the cat in the box with the nuclear decay-based poison trap: when the half-life of the decaying element has passed, the cat can be said to be both alive and dead - held in superposition - until such a time as the box is opened and an observer collapses the superposition into one of the two possibilities.

Superposition is the secret behind the potentially vast power of quantum processors: if you want to look for two outcomes in an equation, a traditional processor will have to perform the calculation twice; a quantum processor, by contrast, can give you both answers at the same time.

To exploit the possibilities offered by quantum computing requires education, which poses a problem: current quantum computers are extremely expensive, and require equipment - such as liquid nitrogen cooling jackets - out of the reach of home users. To help address this issue, the University of Bristol has announced plans to provide public access to its in-house two-bit quantum processor.

Building on the University's publicly-accessible quantum processor simulator, the team is to provide access to to the quantum processor under the Qcloud project so that researchers can experiment with quantum superposition as well as quantum entanglement - the ability to create interference between two photons which links them even when they are physically apart, famously described by Albert Einstein as 'spooky action at a distance.'

Interested parties can use the Qcloud simulator now and pre-register for access to the processor itself ahead of the go-live date of the 20th of September on the official website.

Originally Posted by DriftCarlso, you can give a quantum computer a question, and it will pretty much be able to instantly give you every possible outcome, but what then decides what the best/correct outcome is?

it is a probability system. a good example is whit breaking a code it trying 1M codes in one try an while it is calculating it can be code 1 ,2 3 etc but the system must be designed in such a way that the right answer has the highest probability to happen. so if code 10598 is the right answers than it has to have a bigger chance than all other answerers.

the system collapses at the end of evry calculation so it only gives one answer at the end not 1 maybe 0 but just a plain 1 or 0.

now repeat the calculations 1000 times and viola the answer is the code you got the most.

I'm not very smart so this might sound naive: if ordinary (silicon-based) computer takes twice as long as quantum computer to perform a task which provides both answers to a problem with two answers, why not emulate quantum computer in twice (or whichever factor is appropriate) as much hardware ? Why the hassle with liquid nitrogen and the rest of that fancy machinery for something which sounds as trivial as emulating Intel's 4004 on a 80386SX ?

Originally Posted by AlectoI'm not very smart so this might sound naive: if ordinary (silicon-based) computer takes twice as long as quantum computer to perform a task which provides both answers to a problem with two answers, why not emulate quantum computer in twice (or whichever factor is appropriate) as much hardware ? Why the hassle with liquid nitrogen and the rest of that fancy machinery for something which sounds as trivial as emulating Intel's 4004 on a 80386SX ?

Because some questions have a lot more than two possible answers (e.g. what is the enncryption key for this file?). A normal computer will have to try every possible sanswer one by one, whereas a quantum computer can try every possible answer at once.

However, In order to answer a question like the above, the quantum computer would need to be able to process a lot more than the two bits that the Bristol computer can handle. This is the first step in that direction though.

Originally Posted by ashchapBecause some questions have a lot more than two possible answers (e.g. what is the enncryption key for this file?). A normal computer will have to try every possible sanswer one by one, whereas a quantum computer can try every possible answer at once.

However, In order to answer a question like the above, the quantum computer would need to be able to process a lot more than the two bits that the Bristol computer can handle. This is the first step in that direction though.

the processing power of the quantum computer grows exponentially whit the number of entangled qbits. so a 1 qbit qm can check 1 key at once, a 2 qbut can do 2 .
but when you have a 10 qbit qm you can check 1024 keys at once. but you have to ask it multiple times to be sure that you got the right one.

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